The proposed research project aims at studying different types of 15-hydroxprostaglandin dehydrogenases and ketoreductases. The 15-hydroxprostaglandin dehydrogenase controls the biological inactivation of prostaglandins, whereas the 9-ketoreductase regulates the interconversion of functionally different prostaglandins and 15-ketoprostaglandin reductase catalyzes the reactivation of some inactive metabolites. Several aspects of research on these enzymes will be investigated. These include: (l) purification and characterization (2) regulatory properties (3) antibody production (4) development of radioimmunoassay (5) possible roles in genetic hypertension.